Substrate grinding and polishing disk

ABSTRACT

A grinding disk, surfacing platform, apparatus and method adaptable to a rotary concrete surfacing machine. A media disk is pivotally attached to a surfacing platform to maintain a substantially coplanar alignment of an abrasive or polishing media surface and the underlying substrate to be polished. The surfacing platform engages with rotating arms of the machine in operation and may be readily be detached by rotating in the opposite direction of operation.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of U.S. provisional application No. 62/081,895, filed Nov. 19, 2014, the contents of which are herein incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to the construction industry, particularly in the area of providing a finish to concrete floors within a building or other structure. More particularly, the present invention relates to a grinding disk platform that uses platform-sharing technology to create an apparatus that can produce a full grind polished finish on concrete floors.

For homeowners, retailers, architects and engineers that are choosing polished concrete as a finished floor of choice, aesthetics', uniqueness, ease of maintenance and light reflectivity are a few reasons why this flooring system is quickly becoming one of the most popular and sought after hard surface floor.

Currently the process of polishing concrete requires a great deal of expertise and the use of specialized heavy-duty machines and tooling. The machines currently available in the art are very expensive and labor intensive to use. These machines also require a 3 Phase power supply to operate. Moreover, they are very heavy to move especially on multi-floor construction projects where elevators or winches are required.

Due to the high investment cost some contractors have turned to offering a topical polished surface versus the full grind process. This method may look impressive when initially completed, but is inferior in most situations when one considers that one of the weakest parts of a concrete slab is the surface. Simply abrading the surface, as practiced in the topical polished surface process, will not stand up under heavy foot traffic. In addition this method requires application of a coating material to the surface to produce the shine of the finished surface. Some coating materials do not allow moisture to escape from the concrete, resulting in a buildup of hydrostatic pressure that could delaminate the surfaces and or wear off prematurely requiring additional applications of expensive coatings.

As can be seen, there is a need for an apparatus and method to produce a polished concrete surface that provides an economical way that allows everyone to enjoy the benefits of polished concrete.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a grinding apparatus, comprises a connecting shaft; a media holder comprising an aperture defined through a top surface and a bottom surface of the media holder, the media holder pivotally coupled to the connecting shaft through the aperture for pivotal displacement about the connecting shaft; and a media plate that is removably attached to the bottom surface of the media holder, the media plate comprising a lower surface comprising one of a grinding media, an abrasive media, or a polishing media.

In other aspects of the invention comprises a magnet disposed in the media holder; and a ferrous material attached to an upper surface of the grinding media plate, such that the media plate may be attached to the media holder via magnetic attraction with the magnet. The media plate may be comprised of a ferrous material, and may be operatively coupled to the media holder via magnetic attraction with the magnet. The media plate is preferably formed as a substantially circular disk. In some embodiments, the media plate may also comprise a tapered edge defined around the periphery of a lower portion of the media plate. The media plate may also be formed with a plurality of radially extending channels defined in a bottom surface of the disk.

In another aspect of the invention, the grinding apparatus is provided a hemispherical nut operatively coupled to the connecting shaft, the hemispherical nut comprising an upper rounded surface and the media holder is pivotally disposed on the upper rounded surface of the hemispherical nut. The media holder may further include an attachment adapter attached to the top surface of the media holder, with a rounded depression defined in a lower surface of the attachment adapter. The depression is adapted to pivotally receive the upper rounded surface of the hemispherical nut and the connecting shaft.

In another aspect of the invention, the attachment adapter further comprises a channel defined in an upper surface of the attachment adapter surrounding the connecting shaft; and a flex ring is received in the channel and disposed about the connecting shaft.

In another aspect of the invention, the media holder may also have a slot defined in an outer face of the medial holder, the slot providing an opening between the bottom surface of the media holder and a top surface of the media plate.

According to other embodiments of the invention, a surface grinding apparatus, comprises a platform plate comprising a top surface and a bottom surface; a plurality of brackets attached to the top surface of the platform plate, the brackets defining an opening between the bracket and the top surface of the platform plate; a plurality of grinding assemblies extend from the bottom surface of the platform plate are disposed in spaced apart relation around a periphery of the platform plate, the grinding assemblies comprising a media holder pivotally coupled to the platform via a coupling shaft.

In another aspect of the invention, a media plate is attached to a bottom surface of the media holder, the media plate comprising a lower surface of at least one of a grinding media, an abrasive media, or a polishing media.

In a preferred embodiment of the invention, the grinding assembly further comprises a slot defined in an outer face of the medial holder, the slot providing an opening between the bottom surface of the media holder and a top surface of the media plate. The media holder may also include an attachment adapter attached to a top surface of the media holder, a rounded depression defined in a lower surface of the attachment adapter, the depression adapted to pivotally receive an upper rounded surface of a hemispherical nut, wherein the hemispherical nut is operatively coupled to the connecting shaft. In other aspects of the invention, a channel is defined in an upper surface of the attachment adapter; and a flex ring is received in the channel and disposed between the attachment adapter and the platform plate. Preferably, the flex ring is comprised of a resilient material.

In yet another aspect of the invention, the arms of a rotary power trowel are received in the bracket openings to secure the platform plate with the power trowel with an operating rotation of the power trowel. The platform plate may be detached from the power trowel with a counter rotation of the platform plate.

Another aspect of the invention includes a method for polishing a substrate surface. The method, comprises: providing a powered rotary surfacing machine, comprising a plurality of surfacing arms; providing a platform plate comprising a top surface and a bottom surface; a plurality of brackets attached to the top surface of the platform plate, the brackets defining an opening between the bracket and the top surface of the platform plate; a plurality of grinding assemblies extending from the bottom surface of the platform plate, disposed in spaced apart relation around a periphery of the platform plate, the grinding assemblies comprising a media holder pivotally coupled to the platform via a coupling shaft; and attaching the platform plate to engage the brackets with the surfacing arms to secure the platform plate to the power trowel.

A method of the present invention may also include, attaching a media plate to a bottom surface of the media holder, the media plate comprising a lower surface of at least one of a grinding media, an abrasive media, or a polishing media. The method may further include operating the powered rotary surfacing machine with the lower surface of the media plate in contact with the substrate surface.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective detail view of the invention shown in use.

FIG. 2 is a bottom perspective detail view of the invention shown in use.

FIG. 3 is a top perspective detail view of the invention shown in use with multiple power trowel components omitted to demonstrate interface between blades and platform.

FIG. 4 is a top perspective exploded detail view of the invention shown in use with multiple power trowel components omitted to demonstrate interface between blades and platform.

FIG. 5 is a top perspective detail exploded view of the grinding disk assemblies.

FIG. 6 is a bottom perspective detail exploded view of the grinding disc assemblies.

FIG. 7 is a section detail view of the invention along line 7-7 in FIG. 3.

FIG. 8 is a section detail view of the invention along line 8-8 in FIG. 4 and demonstrating exemplary usage.

FIG. 9 is a section detail view of invention demonstrating exemplary usage/surface adaptation.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

Broadly, an embodiment of the present invention provides a grinding disk platform that has a plurality of grinding disk assemblies disposed on the disk platform. According to other aspects of the invention, the grinding disk platform is adapted to be readily attachable to a standard concrete leveling trowel. In other aspects of the invention, the grinding disk assemblies are attached to the disk platform so that a grinding media carried by the assemblies may be maintained in a substantially coplanar orientation with a concrete surface.

An object of the invention is to use a common platform technology i.e. a common set of design, engineering and production efforts to create an add-on apparatus to the chassis of a rotary concrete finishing machine that converts the machine into a concrete grinder. As such, aspects of the present invention eliminate the need to purchase expensive grinding machines to produce a mechanically ground polished surface.

Another object of the invention may utilize a shared set of common components that can easily interchange various grinding disk media to provide a tool platform that can significantly reduce the number of steps to grind a concrete surface. The grinding disk assemblies may utilize a plurality of heavy-duty metal bonded diamond disc polishing media to produce an exposed aggregate surface. Alternatively, the disk polishing media may include a plurality of resin pads of varying grits to create a level of sheen to meet a desired aesthetic requirement.

Embodiments of the present invention provide a unique design and method that provides an economical way to allow everyone to enjoy the benefits of polished concrete, including a homeowner, who could rent the apparatus from equipment rental companies for a do-it-yourself (DIY) project.

As seen in reference to FIG. 1, a grinding platform 10 is shown coupled to a conventional concrete power trowel machine 38. According to a preferred embodiment of the invention, the platform 10 may be formed as a steel plate, more preferably a disk dimensionally sized to fit a rotary concrete finishing machine 38. The platform 10 provides a base for the components of the invention and an attachment interface for coupling the platform 10 to the power trowel 38.

The conventional power trowel 38 includes a plurality of power trowel blades 40, radially disposed for powered rotation by an engine or motor. The grinding platform 10 may comprise a plurality of bracket hooks 12 attached to a top surface of the grinding platform 10 and a plurality of grinder media assemblies 14 removeably attached to a bottom surface of the platform 10, via an attachment shaft 24, such as a bolt, pin, rivet or screw 24.

As may be seen in reference to FIGS. 3, 4, and 7, the brackets 12 are adapted to receive an arm 40, such as a leading edge of the trowel blades 40 to retain the blades 40 in the bracket 12 as the trowel blades 40 are rotated by the machine 38. The brackets 12 may be formed as a z-shaped steel plate. The brackets 12 may be attached to an upper surface of the platform 10, such as by welds, bolts or screws, and defines a receiving slot 42 when attached to the platform 10. The attachment brackets 12 are preferably aligned so as to engage and interlock with the leading edge of the trowel blades 40 of the rotary concrete finishing machine 38. When attached to the arms 40, the brackets 12 hold the platform 10 to the machine 38 for powered rotation of the platform 10 with the arms 40. The brackets 12 may be attached to the grinding platform 10 so that the platform 10 may be adapted to one or both of a clock wise or a counter clockwise rotation of the trowel blades 40, based on the rotation of the power trowel 38 engine and any intervening transmission assembly. As will be appreciated, the brackets 12 may alternatively be adapted to receive an arm 40 of the power trowel 38, such as if the blades 40 were removed from the power trowel 38.

The grinder assemblies 14 may be disposed in a spaced apart relation on the platform disk 10. In a preferred embodiment, the grinder assemblies 14 are disposed around a periphery of the platform 10. As seen in reference to FIGS. 5, 6, and 8, the grinder media assemblies 14 may comprise a grinding media plate 16 retained within a grinding media holder 18.

The grinding media plate 16 may have substantially flat upper and lower surfaces. In a preferred embodiment, the grinding media plate is formed as a substantially circular disk. A lateral edge of a lower portion of the media plate 16 may have a taper to facilitate movement over surface irregularities in the substrate surface. The lower surface may also be provided with a plurality of radially emanating channels to facilitate the dispersion of ground particulate slurry developed during the grinding of the substrate surface. As will be appreciated, the grinding media plate 16 may be comprised of various grades of hardness and roughness to provide a suitable grinding surface and to obtain a desired finish. Grinding media composition may include steel bonded, ceramic, and resin bonded grit elements. The media grades are selected to correspond to the substrate surface to be ground, such as concrete.

The grinding media holder 18 may preferably be formed as a cylindrically shaped body with a raised lip 21 projecting downwardly from a bottom surface of the holder 18. The grinding media plate 16 may be attached to the holder 18 via a fastener, such as bolts or screws, an adhesive, or a magnet. The media plate 16 is dimensioned so that a top portion of the media plate is received within the raised lip so as to prevent the media plate 16 from becoming dislodged or separated from the media holder 18 while the grinder is in operation. The media holder 18 may have an additional aperture 43 that is dimensioned to receive a retaining pin 44 extending from an upper surface of the media plate 16 to assist retention of the media plate 16, should the media plate 16 encounter a piece of debris, such as a bolt or a nail, that is frequently encountered at a renovation site.

In a preferred embodiment, the grinding media holder 18 may include a magnet 20 disposed within an opening in the bottom surface of the holder 18. In this embodiment, the grinding media plate 16 may be formed from a ferrous material or may have a ferrous material applied to a top surface of the grinding media plate 16. The media plate 16 is then retained within the media holder 18 via magnetic attraction.

Regardless of attachment means between the grinding media plate 16 and media holder 18, to facilitate replacement of the grinding media plate 16, the media holder 18 may further comprise at least one slot 19 extending inwardly from an outer wall of the holder. The slot 19 provides a tool access point between a bottom surface of the media holder 18 and an upper surface of the grinding media plate 16. The user may insert a tool into the slot 19 and pry the grinding media plate 16 from the media holder 18. A replacement media plate 16 may then be inserted into the disk assembly 14, such when the media 16 becomes worn, or to change the media grade so as to obtain a smoother and more polished surface finish. Alternatively, the media plate 16 may be provided with a laterally extending tab that extends through the slot 19 so as to permit ready removal of the media plate 16 from the holder.

As will be appreciated by those familiar with power trowels 38 and rotary disk surfacing machines, changing the directional movement of the trowel 38 over the substrate surface 32 is accomplished by changing the pitch of the rotating disk relative to the surface. When grinding a finished surface to a substrate, it is desirable that the grinding media plate 16 maintain a substantially co-planar orientation with the substrate surface 32 when making directional changes, so as to avoid gouging or scratching the surface. According to certain aspects of the invention, the grinding disk assemblies 14 are pivotally attached to the platform 10 so as to permit a lower grinding surface of the media plate 16 to maintain a flush orientation with the substrate surface 32. As such, the attachment adapter 26 may be pivotally attached to the platform 10 via the bolt 24 coupled to a hemispherical nut 30 retained within the attachment adapter 26.

In a preferred embodiment, the hemispherical nut 30 comprises a rounded upper surface 31 at a top end thereof and a substantially flat surface 33 at a lower end thereof. The lower end of the hemispherical nut 30 may also be provided with a shaped tightening portion 33, such as a hexagon, square, or the like, for holding by a wrench. The hemispherical nut 30 will preferably have a threaded aperture extending from the top of end of the nut 30 so as to threadingly receive the plate bolt 24.

The media holder 18 may further comprise an attachment adapter 26 and the hemispherical nut 30 may be captively retained with the media holder 18 via the attachment adapter 26. The attachment adapter 26 may be formed as a plate corresponding to the shape of the media holder 18, more preferably, it is shaped as a cylindrical disk. An aperture is defined through the center thereof and a rounded depression 27 is defined in a lower surface of the attachment adapter 26 and coaxial with the aperture. The depression is dimensioned to correspond to the rounded upper surface 31 of the hemispherical nut 30 so as to allow pivotal displacement of the media holder 18. The aperture should have a diameter that is larger than that of the plate bolt 24 to allow the media holder 18 and attachment adapter 26 to pivot on the hemispherical nut 30 around plate bolt 24.

The media holder 18 may have a plurality of bores 23 extending through the bottom surface and the top surface of the holder 18. The attachment adapter 26 may include a corresponding plurality of bores 25 defined in at least a bottom surface of the attachment adapter 26 and oriented for alignment with the bores 23 of the holder 18. The media holder 18 may then be removably attached to the adapter 26 via a plurality of fasteners 22, such as rivets, bolts, pins, or screws, to permit servicing of the grinding assemblies 14. Alternatively, the attachment adapter may be secured to the media holder via a bonding agent, or welds.

As best seen in reference to FIGS. 8 and 9, the top surface of the holder 18 may include a clearance hole to receive the lower end of the hemispherical nut 30. The upper rounded surface 31 of the hemispherical nut 30 is received in the rounded depression 27. The attachment adapter 26 may further include an annular channel 29 and a central hub defined in a top surface of the adapter 26. A flex ring 28 may be received in the channel 29 and is disposed between the adapter 26 and the bottom surface of the platform 10. The flex ring 28 may be comprised of a resilient material, such as rubber or other elastomeric material with varying degrees of hardness. The hardness may be selected depending upon whether the platform 10 will be utilized with a walk behind or seated power trowel 38. For a walk behind power trowel 38, the flex ring 28 may be of a softer material having a Shor A durometer of between about 30 to 50, preferably about 40. For a ride-on power trowel 38 or heavier machines, the durometer would be between about 60 to 80, and preferably about 70.

In reference to FIG. 8, with the weigh imparted by the power trowel 38, the bottom surface of the grinding media plate 16 is aligned substantially co-planar with a smooth surface 32 of the substrate material. As directional changes are imparted, such as by tilting the power trowel 38 the grinding assemblies 14 pivotally adapt to maintain the lower surface of the grinding media plate 16 flush with the substrate surface 32, an seen reference to FIG. 9.

The pivoting configuration of each of the media assemblies 14 also permits automatic alignment the grinding surface of the grinding media plate 16 as it encounters an irregularity 36 in the substrate surface 32, the cooperative engagement between the attachment adapter 26 and the rounded surface 31 of the hemispherical nut 30 permit the grinding disk assembly 14 to pivot on the hemispherical nut 30 about the plate bolt 24.

A method for polishing a substrate surface according to aspects of the present invention comprises the steps of providing a powered rotary surfacing machine 38. Attaching the platform plate 10 to engage the brackets with the surfacing arms 40 of the surfacing machine 38 to secure the platform plate 10 to the surfacing machine 38. Attaching a media plate 16 to a bottom surface of the media holder 18 to provide at least one of a grinding media, an abrasive media, or a polishing media, selected based on the desired finish to be obtained and a stage of the surface finishing process. At earlier stages, a coarse grinding media is applied to the substrate surface 32. As the substrate surface 32 is made progressively smoother, an abrasive media may be applied, followed by a final polishing media. The method includes operating the powered rotary surfacing machine 38 with the lower surface of the media plate 16 in contact with the substrate surface 32.

As will be appreciated by those familiar with the operation of rotary surfacing machines 38, the device is steered by tilting the machine 38 so as to impart directional translation by the rotating trowel blades. According to an aspect of the present invention, when the machine 38 is tilted, directional control is provided while the pivoting disposition of the media disk 16, provided by the grinding assemblies 14 maintains the media disk operating surface in a substantially coplanar alignment with the substrate surface 32.

As an additional feature of the present invention, when the grinding disk platform 10 is detached and removed from the chassis of the rotary finishing machine 38, the machine 38 is returned to its original purpose, therefore eliminating the need to purchase a separate piece of expensive power equipment.

It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. 

What is claimed is:
 1. A grinding apparatus, comprising: a connecting shaft; a media holder comprising an aperture defined through a top surface and a bottom surface of the media holder, the media holder pivotally coupled to the connecting shaft through the aperture for pivotal displacement about the connecting shaft; and a media plate attached to the bottom surface of the media holder, the media plate comprising a lower surface comprising one of a grinding media, an abrasive media, or a polishing media.
 2. The apparatus of claim 1, further comprising: a magnet disposed in the media holder; and a ferrous material attached to an upper surface of the media plate, wherein the media plate is removably attached to the media holder via magnetic attraction with the magnet.
 3. The apparatus of claim 1, further comprising: a magnet disposed in the media holder; and the media plate is comprised of a ferrous material, and is removably attached to the media holder via magnetic attraction with the magnet.
 4. The apparatus of claim 1, wherein the media plate comprises a substantially circular disk.
 5. The apparatus of claim 1, wherein the media plate further comprises: a tapered edge defined around the periphery of a lower portion of the media plate.
 6. The apparatus of claim 4, wherein the media plate further comprises: a plurality of radially extending channels defined in a bottom surface of the disk.
 7. The apparatus of claim 1, further comprising: a hemispherical nut operatively coupled to the connecting shaft, the hemispherical nut comprising an upper rounded surface; and the media holder is pivotally disposed on the upper rounded surface of the hemispherical nut.
 8. The apparatus of claim 7, the media holder further comprising: an attachment adapter attached to the top surface of the media holder, a rounded depression defined in a lower surface of the attachment adapter, the depression adapted to pivotally receive the upper rounded surface of the hemispherical nut and the connecting shaft.
 9. The apparatus of claim 8, the attachment adapter further comprising: a channel defined in an upper surface of the attachment adapter surrounding the connecting shaft; and a flex ring received in the channel and disposed about the connecting shaft.
 10. The apparatus of claim 1, the media holder further comprising: a slot defined in an outer face of the medial holder, the slot providing an opening between the bottom surface of the media holder and a top surface of the media plate.
 11. A surface grinding apparatus, comprising: a platform plate comprising a top surface and a bottom surface; a plurality of brackets attached to the top surface of the platform plate, the brackets defining an opening between the bracket and the top surface of the platform plate; and a plurality of grinding assemblies extending from the bottom surface of the platform plate, disposed in spaced apart relation around a periphery of the platform plate, the grinding assemblies comprising a media holder pivotally coupled to the platform via a coupling shaft.
 12. The surface grinding apparatus of claim 11, further comprising: a media plate attached to a bottom surface of the media holder, the media plate comprising a lower surface of one of a grinding media, an abrasive media, or a polishing media.
 13. The surface grinding apparatus of claim 12, the grinding assembly further comprising: a slot defined in an outer face of the medial holder, the slot providing an opening between the bottom surface of the media holder and a top surface of the media plate.
 14. The surface grinding apparatus of claim 11, the media holder further comprising: an attachment adapter attached to a top surface of the media holder, a rounded depression defined in a lower surface of the attachment adapter, the depression adapted to pivotally receive an upper rounded surface of a hemispherical nut, wherein the hemispherical nut is operatively coupled to the connecting shaft.
 15. The surface grinding apparatus of claim 14, further comprising: a channel defined in an upper surface of the attachment adapter; and an flex ring received in the channel and disposed between the attachment adapter and the platform plate.
 16. The surface grinding apparatus of claim 15, wherein the flex ring is comprised of a resilient material.
 17. The surface grinding apparatus of claim 11, further comprising: a rotary power trowel, comprising a plurality of rotating arms, wherein the arms are received in the bracket openings to secure the platform plate with the power trowel with an operating rotation of the power trowel.
 18. The surface grinding apparatus of claim 17, wherein the platform plate is detachable from the power trowel with a counter rotation of the platform plate.
 19. A method for polishing a substrate surface, comprising: providing a powered rotary surfacing machine, comprising a plurality of surfacing arms; providing a platform plate comprising a top surface and a bottom surface; a plurality of brackets attached to the top surface of the platform plate, the brackets defining an opening between the bracket and the top surface of the platform plate; a plurality of grinding assemblies extending from the bottom surface of the platform plate, disposed in spaced apart relation around a periphery of the platform plate, the grinding assemblies comprising a media holder pivotally coupled to the platform via a coupling shaft; and attaching the platform plate to engage the brackets with the surfacing arms to secure the platform plate to the power trowel.
 20. The method of claim 19, further comprising: attaching a media plate to a bottom surface of the media holder, the media plate comprising a lower surface of at least one of a grinding media, an abrasive media, or a polishing media. 